Perifíton - diatomáceas e biomassa - em sistemas semilóticos da planície de inundação do alto rio Paraná.
In 2001 we sampled four semilóticos environments in the Upper Paraná River floodplain - Pau Véio Lake, Leopoldo Ressaco, Ressaco of Bile and Ressaco Manezinho, in order to: a) establish the temporal variations of periphyton biomass; b) the richness of diatoms Periphytic assembly; c) to verify the similarity between periphyton diatomoflórula environments; d) establish the dynamics of diatoms Periphytic assembly; e) identify the types of disturbances that acted on the taxa of diatoms. The collected data were collected monthly in the four backwaters. The substrate was sampled petioles of the aquatic macrophyte Eichhornia azurea Kunth. Analysis of community structural properties was based on biomass measurements (chlorophyll, free dry weight of ash) and richness and density of diatomaceous assembly. They were also applied biological indices for periphyton ranking. abiotic limnological data were obtained (water level, water temperature, turbidity, depth, conductivity, precipitation, pH, O2, NO3, NH4, NT, PT, PO 4). It was observed, regardless of location, higher values of chlorophyll levels in the first five months of 2001, months of higher level of the Parana River (r = 0.48), higher concentration of nutrients, particularly nitrogen, and greater transparency of the water column. In the data set, there was also a greater richness and density of periphyton diatoms assembly when these characteristics were present. They were recorded in all 322 taxa, distributed in 57 genera. In ascending order, the Ressaco Leopoldo had the lowest number of species (197), followed by Pau Véio Lake (205), the Ressaco the Manezinho (218) and the Ressaco the Bilé (222). The environments in general, showed on average 36% of its diatomológica flora consists of rare, ie low frequency of occurrence species. The Leopoldo Ressaco presented the smallest variations in the number of species. The month of July showed a low number of taxa in all backwaters. Beta diversity values were more dissimilar temporally than spatially and richness estimators showed the need for increased sampling effort to assess the system of wealth. In lower level rise period, the density of diatoms was about 10 times lower when compared to the previous period. By comparing the density of periphyton diatoms in each environment in the different hydrological periods, it was not possible to make any significant difference, although the figures are quite different. Among the species, Achnanthidium minutissimum was abundant species that best characterized the environments. It is concluded that the water level is the main controlling force function of diatoms Periphytic assembly in semilóticos environments of the floodplain, mainly by its effect on the availability of nutrients, particularly nitrogen, and the degree of binding to the Parana River . In temporal level, disturbances, of which highlights the human action for the operation of the floodgates of the reservoirs located upstream represented key role in successional dynamics of the species, causing changes in diatom assemblage. It stresses the need for further studies of experimental nature, which allows to identify and measure other environmental parameters (such as competition, the substrate distribution, position in relation to light and wind) that act on the diatomológica assembly, and consequently, on the periphyton .
| Main Author: | |
|---|---|
| Format: | Thesis/Dissertation biblioteca |
| Language: | Portuguese |
| Published: |
Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
2006
|
| Subjects: | Periphyton, Upper Paraná River floodplain, Periphytic biomass, Temporal variations, Diatomáceas, Ciências Ambientais, Brazil, Alto rio Paraná, Estrutura, Comunidades, Perifíton, Planície de inundação, Ecologia, Brasil, Algas de água doce, Freshwater algae, |
| Online Access: | http://hdl.handle.net/1834/10079 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|